Thesis (MPhil (Animal Sciences))--University of Stellenbosch, 2006. / ENGLISH ABSTRACT: A trial was done to determine if there are any differences in the growth performance of finisher pigs in the old conventional type of housing with disease infected pigs, pigs in multi unit housing that were also disease infected and high health pigs in multi unit type of housing. The high health pigs gave the best results when factors like A.D.I., A.D.G., F.C.R., margin over feed cost and carcass weight are compared with the results of the other two treatments. The difference in achievement between the disease infected pigs and the high health pigs were not the same for all the production factors but it was still in favour of the high health pigs. The trial results show just how dynamic pig production has become. From the results it is very clear that there is not any place anymore for the old conventional type of housing in any modern piggery. The time has also come for every pig farmer to look at and evaluate the health status of his piggery and to consider changing over to a high health herd. From a production as well as an economic viewpoint it makes good sense.

Thesis (M. Tech. Agriculture) -- Central University of Technology, Free state, 2012 / The eight-week study was conducted to evaluate the effects of rearing system (indoor vs. outdoor) and energy level on digestibility, growth performance and on the carcass characteristics and visceral organs of pigs. A total of 48 Large Whites (LW) X Landrace (LR) male grower pigs were randomly selected at average weights of 27 ± 4.6.kg and divided into two equal groups that were either raised indoors or outdoors. Within each rearing system, half the pigs were fed on a diet formulated to contain either a normal energy level (14 MJ DE/kg) or high energy level (16.1 MJ DE/kg) resulting in a 2 X 2 factorial design. The pigs were fed ad libitum and water was freely available. Pigs were housed in pairs and each indoor and outdoor pig was offered a space allowance of 0.51 and 13.5 m2 respectively. Indoor pigs were raised in a temperature controlled house consisting of a concrete floor pen while outdoor pigs were on a pasture that predominantly consisted of Kikuyu. Movable gates were used to construct outdoor camps and empty feed bags were used to construct a shade for use as shelter. Faecal collection for digestibility determination took place during week 7 while the growth performance trial was still in progress. Chromium oxide was used to evaluate digestibility and faeces were grabbed before they fell to the ground and sampled. With the exception of ether extracts (EE), the digestibilities of crude protein (CP), digestible energy (DE), crude fibre (CF), neutral detergent fibre (NDF), acid detergent fibre (ADF) and organic matter (OM) were reduced (P <0.05) by rearing pigs outdoors. EE followed the same trend. Feeding the high energy (HE) diet significantly (P >0.05) improved the digestibilities of all the nutrients except for CP. There were no significant interactions (P>0.05) between rearing system and diet for the digestibility of nutrients. Daily gains were similar (P >0.05) between indoor and outdoor pigs. Daily feed intakes and conversions were significantly (P <0.05) lower in indoor pigs. There were no significant (P >0.05) differences between the daily gains and feed conversions of pigs fed either the normal energy (NE) or the HE diet. Indoor pigs fed the HE diet had lower (P < 0.05) feed intakes compared to pigs on the other treatments. In general, average daily feed intakes (ADFI) of the HE fed pigs were significantly (P <0.05) lower than those of the NE fed pigs. The carcass measurements of the indoor and outdoor pigs were similar. The gastro-intestinal tract (GIT) and the liver weights of the outdoor reared pigs were significantly (P <0.05) heavier than those of the indoor reared pigs. Feeding the HE diet led to significantly (P <0.05) higher carcass weights and dressing percentages. Interactive effects (P <0.05) of diet and rearing system were found for lean meat percentage (Lean P) and eye muscle area (EMA). Indoor pigs fed on the NE diet had higher Lean P and EMA while an opposite effect was obtained in the outdoor system. The liver of the NE diet fed pigs was significantly (P < 0.05) heavier than that of the pigs fed the HE diet. It can be concluded that with regard to growth performance and carcass characteristics, the NE and HE diets are respectively best suited for the indoor and outdoor rearing of pigs.

Three experiments were designed to find the most efficient and cost-effective method of meeting the changing amino acid requirements of male and female pigs during the growing period, using the minimum number of feeds. Trial one involved 144, and trial two 192 commercial crossbred (Landrace x Large White) pigs, eight to a pen, with sexes separate. Trial three involved 24 commercial crossbred (Landrace x Large White) pigs and 24 Dalland pigs each penned separately. The amino acid requirements (g/d) for the pigs in all three trials were determined for male and female Landrace x Large White pigs, respectively, using the Pig Growth Model (EFO Software Natal, 1995). Parameter values used for males and females were: growth rate (B, Id) 0.0107 and 0.0120; protein at maturity (Pmat, kg) 39.0 and 28.0; and lipid at maturity (Lpmat, kg) 2.60 and 3.89 respectively. In trials 1 and 2 two iso-energetic (DE 13.8 MJ/kg) basal feeds were formulated; Basal A being a high crude protein (CP) (347g CP/kg) feed designed to meet the amino acid requirements of a male at 20 kg liveweight, while Basal B was a low protein feed (l34g CP/kg) designed to meet the amino acid requirements of a female at 88 kg, thus providing for the most- and the least-demanding pigs on the trial. In the third trial, two iso-energetic (DE 13.8 MJ/kg) basal feeds were again formulated; Basal A being a high crude protein (CP) (347g CP/kg) feed designed to be 20% higher than the amino acid requirements of a male at 20 kg liveweight, while Basal B was a low protein feed (l34g CP/kg) designed to be 20% lower than the amino acid requirements of a female at 88 kg, once again providing for the most- and the least-demanding pigs on the trial. Trials 1 and 2 began when the median weight of pigs in each pen reached 20kg, and were terminated at a pen median of 85 kg liveweight. In the third trial each pig was started on trial when it reached 20kg and was terminated at a weight of 85kg. The first trial involved a phase feeding schedule (20-40, 40-60 and 60-85kg liveweight). The two basal feeds were blended in different proportions to create three feeds per phase: lysine contents in each of the phases in Treatment 1 (TI) were: 11, 8.68 and 7.26g/kg; in T2 they were 9.93, 7.58 and 6.24g/kg; and in T3, 8.85, 6.48 and 5.22g/kg. From the analysis it was established that ADO and time to reach 85kg were the only variables to show significance. ADO exhibited a significant sex x treatment interaction. There were significant differences between treatments for time taken to reach slaughter weight. In addition to a treatment effect there was a sex x treatment interaction for time to slaughter weight. It was expected that males on Tl and females on T3 would exhibit the most efficient performance for their respective sex since these treatments were specifically formulated to meet their requirements. Midway through the trial the pigs contracted enteritis, this affecting the outcome of the trial by inhibiting the potential growth of the pigs. The results of the trial indicated that dietary protein level affected the time taken to reach slaughter weight. This led to the second trial where four treatments were applied. Three of the four treatments followed a fixed feeding schedule, making use of the two basal feeds and a 1: 1 blend of these. The fourth treatment followed a phase feeding schedule, differing between the males (20-65, 65-75 and 75-85 kg liveweight) and the females (20-35, 35-75 and 75-85 kg liveweight). This treatment also made use of the two basal feeds and a 1: 1 blend of these. From the analysis it was found that there were no significant effects of sex and no interactions between feeding treatments and sex; however, ADO, FI, FCE, back fat thickness, time taken to reach 85kg and cost/kg gain were all significantly affected by the feeding treatments. Carcass lean, carcass lipid and total body lipid were also significantly affected by the feeding treatment. This trial was conducted to determine the extent to which differences in growth rate, food intake and carcass lipid could be altered by dietary means. The effect of the level of feed protein was once again shown to be of importance when feeding growing pigs. The third trial was designed to test the efficiency with which two strains make use of the dietary protein supplied. Three treatments were applied: Tl was a choice-feeding treatment in which the pigs were offered the two basal feeds simultaneously. T2 and T3 followed a phase feeding schedule (20-40, 40-60 and 60-85kg liveweight). The two basal feeds were blended in various proportions to create three feeds per phase: the lysine contents in each of the phases in T2 were: 12.2, 10.0 and 7.26g/kg; and in T3 8.1, 6.7 and 5.1g/kg. There were significant sex effects as well as strain x feeding treatment interactions. All variables, ADG, FI, FCE, time taken to reach 85kg and cost/kg gain, with the exception of back fat thickness, showed significance. It was expected that the Dalland strain would perform better than the Cross strain; however, this was not the case, indicating the need for further research into the possibility of feeding according to the genetic makeup of the animal. The importance of meeting the amino acid requirements of the growing pig was evident when summarising the results of the three trials reported here. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.

This study was conducted to determine the influence of factors on the efficiency of protein utilization and the rate of lipid deposition and withdrawal in growing pigs. Two experiments were conducted in total. The first experiment involved fifty-two crossbred entire Large White x Landrace male pigs, individually penned, which were used to test the proposition that the efficiency of protein utilisation is influenced by the body composition of the pig at the start of the trial. The experiment was divided into two phases: in the first period, starting at 20kg liveweight, when 3 pigs were slaughtered to determine the initial body composition of the pigs on the trial, the remaining 48 pigs were divided into three groups, two of which were fed ad libitum, with 11 pigs being offered a feed high in crude protein (HP, 1979 CP/kg) and 19 pigs being offered a low CP (LP, 166g/kg) feed. The remaining 19 pigs were fed HP on a restricted basis; the daily allowance being 0.7 of the mean intake of those pigs fed HP ad libitum. The objective of this initial period was to create three groups of pigs differing in body lipid content. As each pig achieved a protein weight of approximately 5.9kg, predicted to occur when the pigs on the three treatments reached live weights of 35, 39 and 34kg respectively, the pig entered phase 2 of the trial. At this stage three pigs from each treatment (a total of 9 pigs) were slaughtered for carcass analysis, the protein contents being approximately 5.9kg, and lipid contents being 85,98 and 87g/kg for the 3 treatments respectively. During phase 2, the 8 pigs fed HP in phase 1 continued to be fed HP in phase 2; 8 pigs were chosen at random from those fed LP in phase 1 and were allocated the high CP basal feed, while the remaining 8 were given LP; and 8 of the pigs feed-restricted in phase 1 were randomly chosen and fed HP, while the remaining 8 were given LP. All pigs were fed ad libitum during phase 2. Four pigs from each treatment in phase 2 were slaughtered after 1 week and the remaining 4 a week later for analysis of body composition In the first week of the second phase of the trial protein gain was highest (264g/d) on the pigs previously restricted and then fed HP, followed by those previously fed LP and then HP (242g/d), with pigs previously restricted and then fed LP depositing the least amount of protein (192g/d). Pigs fed LP or HP throughout, had protein gains of 217 and 210g/d, respectively. Efficiencies of utilization of dietary protein did not differ significantly between treatments, however, the highest being measured in pigs fed LP throughout (461g/kg), followed in order by those fed LP and then HP (457g/kg), those fed HP throughout (404g/kg), those previously restricted and then fed LP (394g/kg), with those previously restricted and then fed HP being the least efficient (372g/kg). The second experiment involved twenty-six male and twenty-six female crossbred Large White x Landrace pigs, individually penned, which were used to determine the maximum rate at which growing pigs can gain lipid. The experiment was divided into three phases: In the first, starting at 20kg live weight (56 days old), when two males and 2 females were slaughtered to determine the initial body composition of the pigs on the trial, the remaining 24 males and 24 females were randomly allocated to their various treatments. The treatments consisted of a feed high in crude protein (H, 197g/kg), a feed low in CP (L, 166g/kg) and three blends, namely 5OH/5OL (180g/kg) (male diet), 30H/70L (167g/kg) (both male and female diets) and 20H/80L (162g/kg) (female diet). Six pigs from each sex were allocated to each treatment. The EFG Pig Growth Model was used to determine the fat contents (lipid index) on the two feeds available and the three blends, to estimate the best times to sample pigs. It was estimated that phase 1 would terminate at 63 d, phase 2 at 70 d and phase 3 at 77 d of age. At the end of each phase two pigs from each sex and treatment were slaughtered. The lipid contents differed significantly between treatments at the end of phase 2 for the male pigs, with the highest being measured in pigs fed L (108g/kg), followed in order by those fed 70L/30H (86g/kg), those fed 5OL/5OH (74g/kg), and those fed H (68g/kg) with the least lipid content. The lipid contents of the female pigs were highly significantly different at the end of phase 3, with the highest being measured in pigs fed L (147g/kg), followed in order by those fed 80L/20H (124g/kg), those fed 70L/3OH (116g/kg) and the least lipid content from those fed H (115g/kg). As estimated by the EFG Pig Growth Model, the male and female pigs fed L treatment had the highest lipid content and those fed H treatment, achieving their target rate of lipid deposition, with the lowest lipid content. This study indicates that the response in protein gain and in efficiency of utilization of protein of pigs to a given feed is dependent on the amount and quality of the feed given to the animals previously. Also, the maximum rate of lipid deposition can be achieved by monitoring the changes in lipid deposition over a period of time, which enables an enhanced understanding of the theory of food intake regulation in a growing pig. As a result, accurate changes can be made when designing a phase-feeding program for growing pigs. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

Simulation modeling is an active part of animal nutrition. These complex programs rely on mathematical functions to predict the performance of an animal. The Gompertz equation is a simple, but accurate function that fits animal growth data well. In conjunction with allometry, the growth of a specific genotype can be predicted. Only three parameters are needed to sufficiently describe a genotype, viz. protein weight at maturity (Pm), the Gompertz growth rate parameter (B) and the lipid to protein ratio at maturity (LPRm), These descriptors are lacking for commercial pig genotypes in South Africa, and this hinders the use of models in simulating nutrient requirements. It is the aim of this thesis to estimate these parameters in six South African pig genotypes. Thirty pigs from each of six commercial genotypes were analysed using a serial slaughter method in which pigs were slaughtered at 4 and 14 days of age, and at 30, 40, 70, 80, 90 and 100kg live weight. The animals were choice fed and were housed in conventional housing facilities. Analyses for protein, lipid, water, and ash contents of the empty body at the respective weights were performed. The results indicated that there were no significant differences between the six genotypes in terms of mature weights or B of the various body chemical components, or between the B values estimated for all components across genotypes. The mean of the estimated values for Pm, B and LPRm were 38,8 ± 2.1 kg, 0.012 ± 0.004 day(-1), and 1.16 kg/kg respectively and can therefore be used to adequately describe all six genotypes. The assumption made that all body components have a similar B value is supported. To investigate the possible effects of the environment on growth, a comparative trial was performed on 20 pigs each from genotypes 4, 5 and 6 using chambers in which the temperature could be controlled to within 1 degree C of the setting. All other experimental methodologies were similar to those adopted in the first experiment. No significant differences were found between the two housing facilities, in terms of the genetic parameters, within the respective genotypes supporting the findings of the previous trial. It may therefore be possible to estimate B using the live weight and estimating Pm and lipid at maturity using allometry, instead of going to the expense of a full serial slaughter trial. The allometric coefficients relating lipid, water and ash to protein were 1.18, 0.88 and 0.97 respectively. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2002.

The broad objective of the current study was to determine the response of pigs fed on incremental levels of Acacia tortilis leaf meal-based diet. Eight trees of each of the following five dominant leguminous leaf meals; A. tortilis, A. robusta, A. nilotica, A. nigrescens and A. xanthophloea, were individually hand harvested from the same grazing camp at Makhathini Research Station, Jozini, South Africa. The leaf meals were harvested between April and May 2013 after the rainy season at advance stage of maturity. Following the nutritive evaluation of Acacia species, A. tortilis was selected for the feeding experiment. Thirty finishing male F1 hybrid (Landrace × Large White) pigs with an initial weight of 60.6 (s.d. = 0.94) kg were randomly allotted to six dietary treatments containing 0, 50, 100, 150, 200, 250 g/kg DM inclusion levels of A. tortilis leaf meal. Each treatment diet was offered ad libitum to five pigs in individual pens for 21 days. Average daily feed intake (ADFI), body weight, average daily gain (ADG) and gain: feed ratio was measured every week. Blood was collected at the end of the experimental period for the determination of nutritionally-related blood metabolites and activity of Aspartate aminotransferase (AST), alanine amino transferase (ALT) and alkaline phosphatase (ALP). Following a feed withdrawal period of 12 hours, pigs with a mean body weight of 80 ± 15 kg were slaughtered, eviscerated for the collection of livers, kidneys, lungs and heart from each pig and weighed individually using a digital scale. Acacia tortilis and A. xanthophloea leaf meals had the highest CP and fat content (P < 0.01) among all the Acacia species. The NDF and ADF varied significantly across Acacia species (P < 0.05). Acacia robusta had significantly the highest levels of non-structural carbohydrates, whilst A. tortilis had the lowest. The concentration of proanthocynidins varied across the species. Acacia tortilis had significantly high levels (23 g/kg DM) of phosphorus compared to the other species. Acacia nilotica had the highest (P < 0.001) concentration of iron, but it had the lowest (P < 0.01) level of manganese. There was a quadratic decrease in both ADFI and ADG (P < 0.001) with as A. tortilis leaf meal increased. The gain: feed ratio was linearly reduced (P < 0.001) with incremental levels of A. tortilis leaf meal in the diets. Serum concentrations of Fe, AST and ALP increased quadratically (P < 0.01) as A. tortilis leaf meal increased. There was a linear increase in ALT activity with increased leaf meal inclusion. Hepatosomatic index (HSI: liver weight/ body weight x 100), scaled kidney weight and scaled heart weight increased linearly (P < 0.001) as A. tortilis leaf meal increased. There was, however, a quadratic increase in the relative weight of lungs (P < 0.001) as leaf meal increased. In conclusion, the piecewise regression (brocken-stick) NLIN procedure (SAS, 2008; SASA institute Inc.) showed that A. tortilis leaf meal can be included in finisher pig diet up to 150 g/kg DM of feed without negatively affecting growth performance, nutritionally-related blood metabolites, liver enzymes and internal organs of pigs. / M.Sc.Agric. University of KwaZulu-Natal, Pietermaritzburg 2013.

Two experiments were conducted for this thesis, to determine whether an animal should be fed to its genetic potential in spite of this not being achievable due to an on-farm constraint. The first experiment was designed to compare the response of pigs housed either individually or in groups to a range of feeds limiting in lysine between 40 and 85 kg live weight. Two hundred and eighty-eight entire male Large White x Landrace pigs were used. The experiment was divided into two growth periods, i.e. from 40 to 60 kg and from 60 to 85 kg. In each period, pigs were subjected to feed containing one of four dietary lysine concentrations. In Period 1, the lysine concentrations were 11.03 (L1); 9.54 (L2); 8.00 (L3) and 6.51 (L4) g/kg, while in Period 2 these were 7.82 (T1); 6.71 (T2); 5.55 (T3) and 4.40 (T4) g/kg. Pigs fed an L1, L2, L3 or L4 diet in Period 1 were fed a T1, T2, T3 and T4 diet in Period 2, respectively. Three buildings provided the following group sizes and floor-space allowances: House 1 contained eight pigs per pen at 1.94 m2/pig; House 2 contained four or eight pigs per pen at 1.72 or 0.86 m2/pig; and House 3 contained one pig per pen at 1.72 m2/pig. The individually-housed pigs were divided into three feeding levels, i.e. ad libitum, or pair-fed so that feed intakes would match those of ad libitum-fed pigs housed in groups of either 4 (restricted-4) or 8 (restricted-8) pigs per pen in House 2. For all group sizes, feed intake increased linearly as the dietary lysine content increased. However, this increase was significantly lower for 8, when compared with 1 and 4 pigs per pen. The linear increase in feed conversion efficiency with dietary lysine content was similar for all group sizes. However, at any dietary lysine concentration, pigs housed in groups of 8 had significantly higher efficiencies than the pigs housed individually or in groups of 4. Average daily gain increased linearly as lysine intake increased, this increase being the same for all group sizes. However, pigs in smaller groups grew significantly faster than those in larger group sizes for any lysine intake. Protein and lysine retention were unaffected by group size, increasing linearly as lysine intake increased. The efficiency of lysine utilisation (0.45) was not impaired by group size. The pair-fed pigs housed individually (restricted-4 and -8) consumed significantly less feed than the individually-housed pigs fed ad libitum, and this was reflected in their average daily gains, which increased linearly as lysine intake increased, but with the restricted-8 growing significantly slower than the ad libitum or restricted-4 pigs. In all three treatments feed conversion efficiency increased linearly with dietary lysine content, although the restricted-4 and -8 had significantly higher efficiencies than the ad libitum-fed pigs at any dietary lysine content. Protein and lysine retentions were unaffected by feeding level and increased significantly with lysine intake. However, at any lysine intake the restricted-8 pigs had a significantly lower efficiency of lysine utilisation than the ad libitum or restricted-4 pigs. The pigs with floor-space allowances of 0.86 and 1.94 m2/pig consumed significantly less and grew slower than the pigs with floor-space allowances of 1.72 m2/pig at any dietary lysine content. Feed conversion efficiency was unaffected by floor-space allowance and increased significantly with dietary lysine content. Similarly, protein and lysine retentions were unaffected by floor-space allowance and increased linearly as lysine intake increased. The efficiency of lysine utilisation (0.45) remained unaffected by floorspace allowance. It was concluded that when animals are socially stressed, feeding according to the requirement for maximum protein growth produces the best biological performance and carcass composition, with the corollary that, if profitability and biological efficiency is to be maximised, pigs housed in stressful conditions, or those whose future performance is predicted to be below potential because of external stressors, should not be given feed of an inferior quality. The second experiment was designed to determine the extent to which grouping or floorspace allowance would alter the nutrient content of feed chosen by pigs given a choice of two feeds differing in protein: energy ratio between 40 to 85 kg live weight. Three hundred and eighteen entire male Large White x Landrace pigs were used. Two buildings provided the following group sizes and floor-space allowances: House 1 contained nine and eighteen pigs per pen at 1.72 or 0.86 m2/pig; House 2 contained four, nine and fourteen pigs per pen at 1.72; 0.86 or 0.49 m2/pig. Animals were given simultaneous ad libitum access to a high (236 g protein/kg as fed) and a low crude protein feed (115 g protein/kg as fed) in two hardened plastic self-feeder bins placed side-by-side. A training period of six days was used prior to the start of the trial, during which the two feeds were alternated daily. The reduction in the proportion of high protein feed chosen over time was significantly higher for the groups of four and eight, in comparison to the groups of nine and eighteen, contrasting with the steady increase for the groups of fourteen pigs. Similarly, the significant increase for pigs with floor-space allowances of 0.49 m2/pig differed from the significant decrease for pigs with floor-space allowances of 0.86 and 1.72m2/pig. Pigs housed in larger group sizes and smaller floor-space allowances consumed significantly less and grew slower than pigs housed in smaller group sizes and larger floorspace allowances. However, the feed conversion efficiency remained unaffected by group size and floor-space allowance. The non-significant effect on protein retention with increasing group size contrasted with the significant increase associated with increasing floor-space allowance. The results of the two studies were compared to determine whether pigs chose differently depending on the degree of stress and the implication of this choice. Average daily gain was significantly reduced as the group size increased for pigs fed a fixed lysine content and choice-fed. However, this reduction was less severe with choice-feeding than when feeding a fixed lysine content. Increasing the group size significantly reduced the feed intake in pigs fed a fixed lysine content only. The efficiency of protein utilisation remained unaffected as the group size increased for the pigs fed a fixed lysine content. However, at any group size pigs fed lower lysine contents had higher efficiencies than pigs fed higher lysine contents. On the contrary, increasing the group size significantly increased the efficiency of protein utilisation in choice-fed pigs. The average daily gain and feed intake was significantly improved as the floor-space allowance increased but was similar for pigs fed a fixed lysine content and choice-fed. Although the efficiency of protein utilisation remained unaffected by increasing the floor-space allowance for the pigs fed a fixed lysine content and pair-fed, at any floor-space allowance pigs fed higher lysine contents had higher efficiencies than pigs fed lower lysine contents. The results indicate that providing socially stressed pigs a choice between an appropriate pair of feeds differing in protein: energy ratio, does not overcome the reduction in potential growth, but does result in performance similar to that of pigs fed a fixed lysine content. It was concluded that the social stress of grouping or floor-space allowance has no influence on the ability of the animal to select an appropriate dietary combination allowing the expression of potential growth within the constraint(s) of the production system. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.